Welcome to the DateLife project. It is a service for getting chronograms (trees with branch lengths proportional to time) using information from published chronograms (which are ideally based on robust other information, such as fossil calibrations). It can do this from a list of taxa or for an input phylogeny. Note that this approach is inferior to doing a thorough analysis using your own raw sequences or trees and carefully checked calibration points, ideally with appropriate uncertainty: this can be done with tools like BEAST, r8s, RevBayes, treePL, PATHd8, and many more. However, DateLife can be useful for cases where meeting the gold standard is infeasible (arguably for some scientific studies) or overkill (i.e., for crediting students in a field-based taxonomy course for the amount of time represented by their specimens, rather than the number of, say, families). DateLife has multiple components, all of them open:

An R package, datelife for doing the calculations. If you're an R user, this is probably the way to go. It can be installed by first installing the devtools package from CRAN and then doing devtools::install_github("phylotastic/datelife").

DateLife is part of the Phylotastic project, funded by NSF. It uses resources from the Open Tree of Life project, rOpenSci, and TreeBase. To help, please add trees to OpenTree's database! [they can be yours or others']